1. Technical Field
The disclosure generally relates to an ultrasound image registration apparatus and a method thereof, which are able to register two ultrasound images partially overlapped with each other.
2. Related Art
In medical image applications, the image registration processing (or image alignment processing between two images) plays an important role, for example, it is needed by image fusion or three-dimensional computed tomography (CT) serving as a first-stage image processing. When dealing with an image registration of ultrasound B-mode images, it is found that a basic characteristic of the ultrasound image, i.e. speckles in an ultrasound image, makes the image registration difficult for processing. The speckles make it difficult for the optimization step in an image registration processing architecture to achieve global optima, instead, only local optima can be found.
The early image registration processing technique is mainly used to register images obtained through different image-capturing methods (including different detectors), where the images are developed first, and then, an image registration processing is performed. However, if an image registration processing starts only after image-developing operation is complete, a lot of raw data may be lost in the image-developing operation of ultrasound images; moreover, the image dynamic range would be reduced, and thereby increase the impact of noise on the image quality. Therefore, how to improve the accuracy and the processing efficiency of image registration processing has become a major issue for the industry.